H. von Schenck

Oxygen structures on Fe(110)

The adsorption of oxygen on a Fe(110) single crystal has been studied by means of high resolution photoelectron spectroscopy (HRPES) and scanning tunneling microscopy (STM). Core level spectra were ...

Adsorption and bonding of 2-butenal on Sn/Pt surface alloys

The adsorption of 2-butenal on the Pt(111), Pt(111)Sn-(2 x 2), and Pt(111)Sn-(root3 x root3)R30degrees surfaces has been studied by high-resolution photoelectron spectroscopy and DFT calculations. On Pt(111) 2-butenal adsorbs at a threefold hollow in a eta(3)(C,C,O) configuration. A similar geometry is observed for Pt(111)Sn-(2 x 2), although the oxygen coordinates to tin instead of platinum. As the surface coverage of tin increases, as for Pt(111)Sn-(root3 x root3)R30degrees, the most stable adsorption geometry changes to eta(1)(O), where the carbonyl oxygen once again coordinates to tin. The carbonyl bond thus retains an activated character as Pt/Sn alloys are formed. The alkene/surface interaction is, however, dramatically influenced at increasing surface concentrations of tin.

Synchrotron radiation photoelectron spectroscopy study of Pb-Pc thin films on InSb(1 0 0)-(4×2)/c(8×2)

The electronic properties and the thermal stability of a thin film of lead-phthalocyanine deposited on the InSb(100)-(4 x 2)/c(8 x 2) surface were studied by synchrotron radiation core level and valence band photoelectron spectroscopy. The interaction between the overlayer and the substrate was determined by analyzing the photoemission spectra of a thin film and of a single monolayer of adsorbed molecules. Subsequently the monolayer was annealed at increasing temperatures, leading first to a gradual change of the oxidation state of the central lead atom, then to a fragmentation of the macrocycle itself.

CO bonding on tin modified Pt()-(1×2)

The influence of tin on the bonding of CO to Pt(l 10) has been studied using high-resolution electron energy loss spectroscopy, density functional theory and photoelectron spectroscopy. CO binds on-top to platinum at all investigated tin and CO coverages. Bonding of CO in Sn-Pt alloy rows is weakened compared to clean Pt(l 10). However, several different adsorption sites in Pt-only rows, inequivalent with regard to their coordination environment, show very similar characteristics with respect to CO adsorption.

High resolution photoemission study on SnO2 gas sensors

Pd-, Pt-doped and undoped SnO 2 gas sensors were studied by synchrotron radiation photoelectron spectroscopy (SRPES) and laboratory source UPS (ultraviolet photoelectron spectroscopy). Valence band spectra were recorded for photon energies of 60-120 eV (SRPES) and for 40.81 eV (UPS). The spectra were analyzed by factor analysis and generation of difference spectra. A comparison of the samples shows that the doping material of these sensors is not introducing additional states to the surface electronic structure within the limit of detection. This leads to the conclusion that the surfaces of the grains are not enriched with the metal additives.

Corrosive adsorption of Sn on the Pt(110)(1 x 2) surface

Room temperature deposition of Sn on the Pt(110)(1 x 2) surface has been studied by scanning tunnelling microscopy and core level photoelectron spectroscopy. At low coverage Sri is found in three d ...